1. Field
The invention relates to a shift register, and more particularly to a bi-directional shift register capable of operating in a forward direction and a reverse direction.
2. Description of the Related Art
Shift registers have been widely used in data driving circuits and gate driving circuits, for controlling timing in receiving data signals in each data line and for generating a scanning signal for each gate line. In a data driving circuit, a shift register outputs a selection signal so as to write an image signal into each data line. Meanwhile, in the gate driving circuit, the shift register outputs a scanning signal so as to sequentially write the image signal supplied to each data line into pixels in a pixel array.
A conventional shift register generates the selection signal or scanning signal in only a single direction. However, a single scanning direction does not satisfy the entire requirements of LCD products. For example, some display types of digital cameras are rotated according to the placement angle of the camera. In addition, some LCD monitors comprise the function of rotating the monitor, so an LCD display with different scanning turns is required. Therefore, a novel bi-directional shift register capable of outputting signals in a forward direction and a reverse direction is desired.